As we've already mentioned, the GeForce 8800 Ultra doesn't differ all that much from the previous flagship GeForce 8800 GTX from a feature standpoint. Their specifcation, however, differ in that the Ultra's GPU, stream processors, and memory are clocked somewhat higher. We've put together a simple chart to illustrate the main differences:
|GeForce 8800 Ultra||GeForce 8800 GTX|
|Number of Transistors||681M||681M|
|Core Clock (Dispatch, TMU, ROP)||612MHz||575MHz|
|Shader Clock (Stream Processors)||1500MHz||1350MHz|
|# of Stream Processors||128||128|
|Memory Clock||1080MHz (2160MHz)||900MHz (1800MHz)|
|Memory Interface||384 bits||384 bits|
|Frame Buffer Size||768MB||768MB|
|Max Power 175W||175W||175W|
As you can see, the GeForce 8800 Ultra uses what is essentially the same GPU at the GTX, which is built using TSMC's 90nm fabrication processes. With the Ultra, however, NVIDIA has re-spun the chip to allow for higher clock speeds at a similar power budget. In comparison to the GTX, the GeForce 8800 Ultra's core GPU clock speed has been increased to 615MHz (up from 575MHz), the shader clock has also been increases to 1.5GHz, and the memory clock is up to 1.08GHz. With the increased clocks comes a higher fillrate, better shader compute performance, and of course more memory bandwidth. All of which will improve overall performance.
From a pysical standpoint, the GeForce 8800 Ultra looks almost nothing like the GeForce 8800 GTX at first glance, thanks to its redesigned cooler. Underneath the cooler, however, lies the same 10.5" PCB. Instead of the rounded cooler found on the GTX, the Ultra is equipped with a large rectangular shroud that runs the length of the card. The front edge is vented just like the GTX, but the fan is offset and rises above the edge of the PCB by about an inch. This design allows NVIDIA to use a slight larger heatsink to cool the GPU and RAM mounted to the front of the PCB.
Like the GTX, the mounting plate on the Ultra is home to a pair of dual-link DVI outputs and a TV/HD video output. And along the top edge of the PCB lie the very same pair of SLI edge connectors.